Calling all Yanmar Gurus...

rufus1138 · Jun 12, 2014

the turning thing is odd, have you looked at the prop to see what kind of condition its in? idk that these arent all related, the smoking could be over-fuelling or over loading, im not sure but the 4.5 kts is a little low and the turning part is just bizarre.

woodster · Jun 12, 2014

as far as the throttle drifting back there is a cable clamp for that problem sbo and defender have them

kito · Jun 12, 2014

Do you know the make, od and pitch of your prop?. I'm curious too about 4.5 top end and pulling to port hard.

Calif. Ted · Jun 12, 2014

1. As others have noted look for a clamping device on the engine end of throttle cable to adjust tension. Edson pedestals use a bolt to adjust the tension on the axle of the throttle lever. It is located beneath the compass.
2. I'd check the exhaust elbow for clogging if you don't know it's current condition to be good.
3. Sorry, I got nothing' but a lot of "could be's" on that.

kito · Jun 12, 2014

Did you have this boat before all the work the mechanic done? If so, were these problems occuring previously? It seems like all the issues are when in gear with the shaft spinning. Do you feel any vibration that my not be normal? Seems to me the alignment is out of wack. When under sail does the rudder turn freely?

Dave602 · Jun 12, 2014

#1 sounds like cable clamp
#2 sounds like a loading problem, badly fouled bottom/prop (any vibrations) or clogged mixing elbow. might have a diver check the prop for fouling. cheaper than a haul out.
#3 couldn't speculate

crosswind · Jun 12, 2014

I have been searching the internet for any info I could find on yanmar marine diesels and have about 6 pages in a word doc of cut-n-paste info on history, I.D., parts, mechanical drawings, original manuals, tips/tricks, pearls. Etc... Give me an email and I can send it to you
I was researching for my own knowledge.

CW

kloudie1 · Jun 12, 2014

I am no guru, but I will confirm others words.
A diesel "throttle" actually sets an RPM target for the engine.. The governor then adds fuel to try to get to that RPM.. What you are describing is a classic diesel overload. The engine is making enough horsepower and burning all the diesel until it hits a limit where there is not enough air to burn the fuel that is being injected. The overload can be a bunch of things like too much propeller pitch or a fouled prop and/or hull bottom. It can also be caused by restrictions on the intake air side or the exhaust side. You checked intake so ya need to pull the exhaust elbow and make sure it is open ..I am assuming that the mechanic work did not involve pulling the diesel injection pump?? . If the injection pump was removed, there could be a timing issue ..
Throttle: If you remove the compass and compass holder on top of the pedestal, look at the casting that holds the throttle and the shift levers. On top of that casting you will see a little recessed screw just above the throttle shaft. That set screw can be tightened carefully to hold the throttle setting but still allow the shaft to move. You probably have a Merriman Yacht Specialties pedestal. There is a diagram of it in the downloads section.

Benny17441 · Jun 12, 2014

Had an h27 with similar maladies.
1) The sliding throttle lever. I had a piece of cardboard covered with tape that would attach to the pedestal with Velcro and a string which could be wedged against the lever to hold it in place.
2) The smoking at WOT is likely overfueling and could be due to a fouled prop/hull. This could also be related to the boat turning under power.
3) The boat turn; been there but the diagnosis of the actual cause was not clear cut. First make sure the condition does not manifest itself under sail and only under power. At the time I was experiencing a loss of power and the mentioned steering pull to port. I first called my diver and asked him if he had cleaned the prop on his last visit a couple of days earlier and he assured me that he had. I gave the engine a tune up by adjusting the valves gap, replacing the filters and removing and cleaning the exhaust mixing elbow. Next time I went out the engine had regained power and the steering pull was gone. Your boat should be making at least 5.5 knots under power under calm conditions. Check the hull and prop for marine growth and clean before doing anything to the engine. A clogged mixing elbow would be my guess if after cleaning the hull and prop the condition persists.

Scott T-Bird · Jun 13, 2014

You don't mention what color smoke. Since you are the proud new owner of a Yanmar 1GM10, get a SELOC catalogue for your engine. It will be invaluable. Prepare yourself by doing a lot of reading and study the parts. It will be too expensive to rely upon the mechanic and you will never be satisfied that you are getting the proper service if you don't gain the knowledge for yourself. I went thru the same learning curve when we bought our 27' boat with 1GM inboard.

For starters, the boat may be slightly underpowered. That said, 4.5 knots is unacceptable. Our 1GM achieved 6 knots (5,700 pound boat) in lake waves. It is very likely that your bottom condition is badly fouled with marine growth. I found that just a healthy coat of algae slime reduced speed by more than 1/2 knot and significantly increased the BLACK smoke at WOT. I'm in fresh water so have never experienced the nasties that you may have growing on the bottom. My prop was over-pitched (sellers explained that is was compensation for being slightly underpowered and needing the power running against the tide on Shrewsbury River). I don't know if the argument holds water, but the max rpms achieved was too low and inevitably caused other problems.

BTW, you need to fix your tac or obtain one that works. You are totally in the dark without a functioning tac. You need to learn the distinction between black smoke, white smoke and gray smoke and the distinct causes.

Your throttle cable is a minor nuisance and should be easily remedied. I set my throttle with a bungy, which seemed to assist the cable screw since it never quite held even when tighted.

Look at the orientation of the shaft as it exits the hull. Don't laugh ... mine is offset, possibly so the shaft can be removed without removing the rudder. I also thought that it negated prop pull to one side in reverse. I've always had a strong pull to one side as the rpms increase while running along in forward.

You should not delay in learning about your engine. From the sound of it, you have already observed some alarming problems. I went thru the experience of watching my 1GM display alarming symptoms and ended up replacing it with a new 2-cylinder Yanmar for a total cost of close to $10 K. I wanted the re-power for various reasons, but it isn't how most people would choose to spend money on an aging, small boat. If you don't learn to take care of that engine by yourself, you can find yourself forced to make some uncomfortable decisions.

tfay412 · Jun 14, 2014

The smoke is injectors. Change that and you should be good to go. The throttle issue you just need a cable brake. Sailboatowners.com sells these. The turning is most likely a bent wing on your keel. You will need to haul out and have a yard bend it back for you. Any other issues feel free to ask.

tfay412 · Jun 14, 2014

If it was the elbow you would have a loss of power as well. But seems like maintenance has been neglected on your motor. So change the elbow and the injector put a cable brake on your cable and you should be good to go mechanically.

MDS · Jun 14, 2014

Definitely pull the exhaust elbow and check for internal corrosion and pinholes. If you know that it's the original, I would replace it regardless of condition. With the elbow off, you need to look inside the exhaust port on the cylinder head. Yanmar 1GM's have a tendency for the port to clog up with very hard carbon if the engine is not run consistently at high RPM's. Mack Boring, the Northeast distributor for Yanmar's, told me that the engine should be "run hard".

If the elbow is leaking, the salt and carbon can form a rock-like solid that needs to be removed very carefully. There can be damage to the cylinder head underneath these deposits. I ended up replacing both the head and the exhaust elbow. If you find that the port is clogged, I would seriously consider removing the head. The exhaust valve could be burnt.

Good luck!

BobM · Jun 14, 2014

Go for a swim

Even sitting on the mooring you can pick something up. I once found a lure and some line on board. Perhaps your prop has fouled...or you rudder has broken and is spinning on the shaft...mixing elbow is always a possibility if the engine wont rev up. Does it happen both in neutral and in gear?